Among animals, humans are unique, but why?

  • The Leakey family has been studying fossils in Eastern Africa since 1931, when Dr. Louis Leakey led an expedition to Olduvai Gorge, in what is now Tanzania. Louis and Mary Leakey’s middle son, Richard, eventually took over the family legacy. Richard married Meave Epps when she worked for his father and they began exploring Kenya’s Lake Turkana Basin in the late 1960s. Richard and Meave’s daughter, Louise, also became a paleontologist focusing on fossils in the Lake Turkana area. Today, both Meave and Louise Leakey are National Geographic Explorers-in-Residence. Together, they have discovered some of the most significant paleoanthropologic fossils in history.  

    This video is an excerpt from the film Bones of Turkana. The film takes place in the area around ancient Lake Turkana. The area is known as a cradle of human life. Evidence shows that hominids may have lived near Lake Turkana 4.2 million years ago. Bones of Turkana, which highlights the Leakeys’ careers, gives greater insight into fossil-hunting, as well as depicting the lives of some human ancestors.

    This video from Bones of Turkana focuses on some of the traits that define us as modern humans. The three traits described are bipedalism, language, and tool making.

    This video assumes some familiarity with the theory of evolution, the process of how organisms developed from earlier forms of life. Evolution is not a linear process, but a dynamic one. One species does not morph directly into another, but diverges from its ancestors. Evolution takes place throughout a population over a long period of time, due to environmental pressures. This video sometimes uses the phrases “more advanced” or “less advanced” which actually don’t apply to evolution. Species evolve to fit the particular environment that they are occupying at a given time, not to “advance” to a different evolutionary stage.

    1. According to the video, what are the traits that define us as modern humans?

      Bipedalism, tool making, and language define us as modern humans.

    2. What environmental pressures are thought to have influenced bipedalism?

      Between 6 million to 10 million years ago, areas with dense tree cover gradually changed to vast grasslands with fewer trees. In order to survive these changing environments, hominids had to adapt from living and moving primarily in trees to being able to walk upright greater distances across open plains.

    3. How is bipedalism related to language and tool making?

      Once hominids were able to free up the use of their hands by walking upright on two legs, they were able to focus on other activities, such as tool making.

    4. How did tool making affect the lives of hominids?

      Tool making allowed hominids to get more use from available resources. They could hunt more food and expend less energy to do so.

    5. How did tool making impact the advent of language?

      Tool making increased the need and opportunity for hominids to share knowledge of tool making and exchange materials with other groups.

  • Term Part of Speech Definition Encyclopedic Entry
    anthropology Noun

    science of the origin, development, and culture of human beings.

    Encyclopedic Entry: anthropology
    biological adaptation Noun

    physical change in an organism that results over time in reaction to its environment.

    bipedalism Noun

    form of movement where an animal consistently uses two legs for standing or walking.

    evolution Noun

    change in heritable traits of a population over time.

    field work Noun

    scientific studies done outside of a lab, classroom, or office.

    Encyclopedic Entry: field work
    fossil Noun

    remnant, impression, or trace of an ancient organism.

    Encyclopedic Entry: fossil
    genetic mutation Noun

    change to the genetic structure of an organism.

    hominid Noun

    biological family of primates, including humans, chimpanzees, gorillas, and orangutans, and their ancestors.

    language Noun

    set of sounds, gestures, or symbols that allows people to communicate.

    Olduvai Gorge Noun

    large valley in Tanzania, known for its abundance of archaeological sites.

    paleontology Noun

    the study of fossils and life from early geologic periods.

    Encyclopedic Entry: paleontology
    technology Noun

    the science of using tools and complex machines to make human life easier or more profitable.